Cryptogamie,Mycologie, 2009, 30 (4): 363-376 © 2009 Adac. Tous droits réservés Composition and characterization of fungal communities from different composted materials SusanaTISCORNIAa, Carlos SEGUÍ a &LinaBETTUCCIa* aLaboratorio de Micología. Facultad de Ciencias-Facultad de Ingeniería. Universidad de la República. Julio Herrera y Reissig 565,Montevideo,Uruguay Résumé – L’analyse des communautés de champignons provenant des composts préparés avec différentes matières premières a été menée pour évaluer l’abondance et la fréquence des espèces qui pourraient constituer un risque pour les plantes, les animaux ou la santé humaine. Un total de 40 405 × 103 propagules correspondant à 90 espèces a été dénombré dans 30 échantillons de deux composts de composition différente. Douze de ces espèces sont thermo-tolérantes, trois sont thermophiles et les autres sont des espèces mésophiles. Acrodontium crateriforme, est l’espèce la plus abondante, présente dans presque la moitié des échantillons de compost préparé principalement à partir de déchets de poils de l’industrie du cuir. D’autres espèces, Aspergillus spp, Monocillium mucidum, Penicillium spp. Paecilomyces variotii, Candida sp. et Humicola grisea var. thermoidea étaient aussi présentes. Le compost composé de déchets de Ligustrum et d’écorces de riz mélangés avec des déjections de poulets est caractérisé par la présence de Aspergillus fumigatus, espèce présente dans presque tous les échantillons, et par Penicillium spp., Fusarium spp., Emericella nidulans, Emericella rugulosa et Humicola fuscoatra. Toutes ces espèces ont été mentionnées dans d’autres composts de différentes origines. Plusieurs d’entre elles sont importantes dans la biodégradation et d’autres sont des antagonistes vis-à-vis des agents pathogènes. Les deux composts peuvent être utilisés séparément ou ensembles pour améliorer la nutrition du sol et participer à la lutte biologique. Abstract – The analysis of fungal communities of two composts prepared with different raw materials were conducted to evaluate the abundance and frequency of species that could constitute a risk for plant, animal or human health. A total of 40 405 × 103 propagules corresponding to 90 species were found in 30 samples of two composts of different composition. Twelve of the species were thermotolerant, three were thermophilic and the other species were mesophilic. Acrodontium crateriforme present in nearly half of the samples of compost prepared mainly with hair waste from leather industry was the most abundant species. Several other species as Aspergillus spp., Monocillium mucidum, Penicillium spp.,Paecilomyces variotii, Candida sp. and Humicola grisea var. thermoidea were present. The community prepared with Ligustrum pruning wastes and rice hull mixed with chicken mess was characterized by Aspergillus fumigatus, present in nearly all samples, and by Penicillium spp., Fusarium spp., Emericella nidulans,Emericella rugulosa and Humicola fuscoatra. All the species are commonly found in composts of different origins. Several are important in biodegradation and in suppressive pathogen abilities. Both composts can be used separately or together to enhance the nutritional and suppressive abilities of soils. Basidiomycetes anamorphs / oleaginous fungi / thermophilic / thermotolerant / mesophilic fungi *Corresponding author:Lina Bettucci Fax and telephone: 598 2 712 0626 email: [email protected] 364 S. Tiscornia, C. Seguí &L. Bettucci INTRODUCTION Composting is the biological conversion of solid organic waste into fertilizer and other products, in a stable substance that can be handled, stored, transported and applied to field without affecting the environment. The high organic matter content and the biological activity make compost also effective in erosion control, biofiltration, bioremediation and production of biogas (Anastasi et al., 2005). The use of composts could constitute a suitable way to avoid some foreign chemical products and also constitute soil conditioner and organic fertilizer (Hoitink &Boehm, 1999). Substantial changes in chemical composition, microbial populations and species abundance during the various temperature stages along the composting process occur. At the end of the process, when compost is ready to be used and material is no longer self heating, temperatures fall and the finished compost has a high microbial diversity (Persson et al., 1995). Fungi play an important role in composting and compost applications, especially for their ability to use complex carbon sources and to suppress soil- borne and foliar plant pathogens (Hadar & Mandelbaum, 1992). Probably their presence were not incidental as nearly all of them are capable of degrading at least one of the major polymer component of hemicelluloses, cellulose and pectin in litter and other organic resources (Domsch et al., 1980). Proper composting effectively destroys pathogen and weed seeds through the metabolic heat generated by microorganisms during the process (Crawford, 1983), but composts may be re-colonized after the end of the process mainly by soil microorganisms (Chang &Hudson, 1967). The use of hair save unhairing techniques has conducted to an increasing production of waste hair in the leather manufacturing industry. The composting hair waste of bovine hide for agricultural fertilization is one of its most promising uses due to the high nitrogen content of hair (Barrena et al., 2006). The complementary plant waste, as co-substrate, gives a more stable product at the end of the process. Composting ornamental plant wastes and wastes with high nitrogen content co-substrates is a frequent practice for organic fertilizer production. The aim of this study was to describe the species composition and their abundance in fungal communities present in commercial mature composts produced with different waste materials and used in agriculture, in order to detect potential plant, animal or human pathogens. MATERIALS AND METHODS Composts sampling procedure Two types of commercial composts prepared with different waste products were analyzed. One was prepared using 50% of waste hair from the leather manufacturing industry, 45% of bovine rumen and 5% of Eucalyptus sp. sawdust as raw materials (HL). The other was prepared with rice hull mixed with chicken mess 50% and 50% of Ligustrum sp. pruning waste (LG). In the manufactures, composts were stocked in piles of the following dimensions: 0.90 m high × 1.5 m large × 150 m long. From each of the 15 piles of both types of composts, five fresh samples of 100 g were taken from the 10 cm under the surface and nearly 500 g of this composed sample was placed in a Fungal community of composts 365 polyethylene bag, transported to laboratory and stored at 5ºC until processing one day after sampling. Then nearly 100 g of each sample were dried to determine the percentage of compost humidity. A quantity of fresh compost equivalent to 10 g of dry compost was used to fungal analysis of samples. Fungal isolation Fungal isolations were performed using the dilution plate method. Colonies obtained by this method are derived from fungi that have exploited any material. Compost dilution was prepared using the equivalent of 10 g of dry compost in 90 ml of sterile distilled water and diluted to obtain 1: 1000. One ml of this final dilution was deposited onto Malt-Agar 2% Chloramphenicol 100 µg/l medium. Ten plates from each compost sample were incubated at 25°C and 37ºC. The emerging colonies were successively numbered. Each colony was subcultured for identification by means of conventional mycological methods and the main current taxonomic sources were used in identification procedures. Cultures which failed to sporulate following incubation under black light or those for which conventional mycological methods resulted in an uncertain identification were identified by means of molecular methods. DNA was extracted and purified following the protocol of Lee & Taylor (1990). ITS rDNA was amplified with primers ITS 4 an ITS 5 (White et al. 1990), visualized with UV light in agarose gel (1%) and the amplified segments were sequenced by Macrogen Korea. Data analysis The relative density of isolation was calculated as the number of propagules forming colonies of a given fungus, by gram of dry compost. To evaluate to which extent the complete fungal community was revealed by sampling, the abundance distribution and species accumulation curves of composts incubated at both temperature were performed. Moreover the relative abundance curves were compared to lognormal theoretical model using the Kolmogorov-Smirnov test (Krebs, 1989). Diversity was measured for each incubation condition of both composts by means of Shannon diversity index with computer package MVSP for Windows (Kovach Computing,Anglesey, UK). To evaluate differences in fungal composition among composts, a simple correspondence analysis using STATISTICA Data Analysis Software Products was carried out using the species with the mean number of propagules equal or higher to 10 × 103 per gram dry compost, at least, in any of the composts at 25ºC or 37ºC (Howard &Robinson, 1995). RESULTS A total of 40 405 × 103 propagules corresponding to 90 species were found in 30 compost samples, 24 845 × 103 propagules belonging to 48 taxa from 15 samples of HL compost and 15 560 × 103 propagules belonging to 62 taxa from 15 samples of LG material. A great variability in the number of propagules (Table 1) and in the species composition per g of dry compost (Table 2) was observed in each of the 15 samples